Assembly method of carriage assembly of magnetic disk drive

ABSTRACT

In a method of assembling a carriage assembly, all first magnetic head assemblies facing first surfaces of magnetic disks are attached to associated arms of the carriage. Each of the magnetic head assemblies is fixed to one side surface of an associated one of the arms, by fitting and calking the mount portion of the first magnetic head assembly in the through-hole of the associated arm. Subsequently, all second magnetic head assemblies facing second surfaces of the magnetic disks are attached to the arms. Each of the second magnetic head assemblies is fixed to the other side surface of the associated one of the arms, by fitting and calking the mount portion of the second magnetic head assembly in the through-hole of the associated arm.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an assembly method of a carriageassembly in which magnetic head assemblies are assembled in a carriagewith a plurality of arms of a magnetic disk drive.

2. Description of the Related Art

In a magnetic disk drive using a magnetic disk, a magnetic head is movedover a recording surface of the magnetic disk and data is recorded ontracks provided on the recording surface.

A magnetic head assembly including a magnetic head is supported on arotatable carriage. The carriage is rotated by means of a voice coilmotor so that the magnetic heads are moved relative to the magneticdisk.

Recently, in order to increase a memory capacity, a magnetic disk driveis provided with a plurality of, for example, two or three magneticdisks. The magnetic disks are rotated and magnetic head assemblies aremoved in a swinging manner over recording surfaces provided on top andbottom surfaces of each magnetic disk. Thereby, data is recorded on therecording surfaces.

In this type of magnetic disk drive having a plurality of magneticdisks, a plurality of arms are provided on the carriage. A plurality ofmagnetic head assemblies are attached to the arms such that eachmagnetic disk is sandwiched by the magnetic head assemblies on bothsides.

According to one assembling method, there are provided a carriage havinga plurality of arms each having a through-hole, and a plurality ofmagnetic head assemblies having cylindrically projecting mount portionsdesigned to be fitted in the through-holes. The mount portions arefitted in the through-holes from both ends of the through-holes andfixed by calking. Thus, each arm is provided with a pair of headassemblies.

According to another assembling method of the so-called "interlock"type, there are provided magnetic head assemblies having cylindricallyprojecting first mount portions designed to be fitted in through-holesof the arms, and magnetic head assemblies having cylindricallyprojecting second mount portions designed to be fitted in the firstmount portions. The first mount portions are fitted in the through-holesfrom first ends of the through-holes, respectively, and the second mountportions are inserted in the through-holes from second ends of thethrough-holes, respectively. The inserted end portions of the secondmount portions are fitted in the end portions of the first mountportions and are fixed by calking. According to this interlock-typemethod, the thickness of each arm can be reduced by a degreecorresponding to overlapping between the first and second mountportions.

In the assembly, high precision is required. Specifically, small-sizedmagnetic head assemblies are conventionally attached to small-sized armsarranged with small intervals by manual work, and not by mechanicalwork.

In the former assembly method, the mount portions of the magnetic headassemblies are manually inserted in the through-holes of the arms fromboth sides of the through-holes so that all the magnetic head assembliesare situated in predetermined positions, i.e. each pair of magnetic headassemblies are situated to face each other inwardly between adjacent twoof the arms.

At this time, since the mount portions of the magnetic head assembliesare simply inserted in the through-holes of the arms, the magnetic headassemblies are unstable and tend to be displaced.

Thereafter, a calking steel ball is passed through the inner holes ofthe mount portions under pressure, thereby fixing the mount portions tothe arms by calking. The steel ball has a diameter slightly greater thanthe inside diameter of each mount portion. Thus, with the passing of thesteel ball under pressure, each mount portion is deformed so as to biteinto the inner surface of the associated through-hole and fixed to theassociated arm. Thereby, the magnetic head assemblies are assembled andsituated to sandwich the magnetic disks from both sides.

On the other hand, according to the latter assembly method, the firstmount portions are manually inserted in the through-holes of the armssuccessively from the first ends of the through-holes, and the secondmount portions are inserted in the through-holes from the second ends ofthe through-holes and fitted in the first mount portions. As a result,each pair of magnetic head assemblies are situated to face each otherbetween adjacent two of the arms.

At this time, since the mount portions of the magnetic head assembliesare simply inserted in the through-holes of the arms, the magnetic headassemblies are unstable and tend to be displaced.

Thereafter, a calking steel ball is passed through the inner holes ofthe second mount portions under pressure, thereby fixing the first andsecond mount portions to the arms by calking.

In each of the above assembly methods, a great deal of time is needed toattach the magnetic head assemblies to the arms. Specifically, in thecase where the magnetic head assemblies are set, while a first group ofmagnetic head assemblies are unstably set on the arms, a second othergroup of magnetic head assemblies need to be set on the arms.

This process must be carried out carefully since the second set ofmagnetic head assemblies must be set without moving the already setfirst group of magnetic head assemblies, by making use of narrow spacesbetween the arms.

In particular, in the interlock-type assembly method, a first group ofmagnetic head assemblies are unstably disposed on first surfaces of thearms, and the first and second mount portions are engaged in thethrough-holes. These steps tend to displace the already set magnetichead assemblies (by external force), and require careful handling.

The work with low efficiency is thus continued from the fixation of thefirst magnetic head assembly to the fixation of the last magnetic headassembly. The work load on the operator is considerably great, and agreat deal of working time is needed. Consequently, the magnetic headassemblies cannot be attached to the carriage efficiently.

SUMMARY OF THE INVENTION

The present invention has been made in consideration of the abovecircumstances, and its object is to provide a method of assembling acarriage assembly, which makes it possible to easily attach magnetichead assemblies to a carriage, thereby reducing a work load on anoperator.

In order to achieve the above object, according to a method ofassembling a carriage assembly as recited in claim 1, all first magnetichead assemblies facing first surfaces of associated magnetic disks arefixed to first surfaces of arms by inserting and calking mount portionsof the first magnetic head assemblies in through-holes of the associatedarms. Then, all second magnetic head assemblies facing second surfacesof the magnetic disks are fixed to second surfaces of the arms byinserting and calking mount portions of the second magnetic headassemblies in the through-holes of the associated arms.

According to an assembly method of a carriage assembly as recited inclaim 3, all first magnetic head assemblies facing first surfaces ofassociated magnetic disks are fixed to first surfaces of arms byinserting and calking first mount portions of the magnetic headassemblies in through-holes of the associated arms. Then, all secondmagnetic head assemblies facing second surfaces of the magnetic disksare fixed to second surfaces of the arms by inserting and calking secondmount portions of the second magnetic head assemblies in the first mountportions of the first magnetic head assemblies.

According to the assembly method as recited in claim 1, all the firstmagnetic head assemblies facing the first surfaces of the magnetic disksare easily attached to the associated arms by making use of wide spacesprovided by alternate arrangement of the head assemblies. These magnetichead assemblies are fixed to the arms by calking. Subsequently, all thesecond magnetic head assemblies facing the second surfaces of themagnetic disks are attached to the arms. In this case, the adjacentfirst magnetic head assemblies facing the first surfaces of the disksare already fixed and are not dislocated even if an external force isapplied. Thus, careful work is not required, and the second magnetichead assemblies can easily be attached by making use of the spacesbetween the arms.

Therefore, the magnetic head assemblies can be attached to the arms ofthe carriage with a less work load, and the work time can be reduced.

Similarly, according to the assembly method as recited in claim 3, thefirst magnetic head assemblies are already fixed to the arms by calkingwhen the second magnetic head assemblies are to be attached to the arms.Even if an external force is applied, the first magnetic head assembliescannot be dislocated. Thus, careful work is not required, and the secondmagnetic head assemblies can easily be attached by making use of thespaces between the arms.

Therefore, with a less load of work and less work time, the magnetichead assemblies can be attached to the arms of the carriage by theinterlock-type method.

Additional objects and advantages of the invention will be set forth inthe description which follows, and in part will be obvious from thedescription, or may be learned by practice of the invention. The objectsand advantages of the invention may be realized and obtained by means ofthe instrumentalities and combinations particularly pointed out in theappended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate presently preferred embodiments ofthe invention and, together with the general description given above andthe detailed description of the preferred embodiments given below, serveto explain the principles of the invention.

FIGS. 1 and 2 show a magnetic disk drive to which an assembly method ofthe present invention is applied, in which:

FIG. 1 is a perspective view showing the structure of the entiremagnetic disk drive, and

FIG. 2 is a partially broken side view showing a carriage assembly ofthe magnetic disk drive;

FIGS. 3 to 6 show an assembly method according to a first embodiment ofthe present invention, in which:

FIG. 3 is an exploded perspective view illustrating a step of attachingfirst magnetic head assemblies to arms of a carriage,

FIG. 4 is a cross-sectional view illustrating a step of fixing the firstmagnetic head assemblies to the arms by calking,

FIG. 5 is an exploded perspective view illustrating a step of attachingsecond magnetic head assemblies to the arms of the carriage to which thefirst magnetic head assemblies have been fixed, and

FIG. 6 is a cross-sectional view illustrating a step of fixing thesecond magnetic head assemblies to the arms by calking; and

FIGS. 7 to 10 show an assembly method according to a second embodimentof the present invention, in which

FIG. 7 is an exploded perspective view illustrating a step of attachingfirst magnetic head assemblies to arms of a carriage,

FIG. 8 is a cross-sectional view illustrating a step of fixing the firstmagnetic head assemblies to the arms by calking,

FIG. 9 is an exploded perspective view illustrating a step of attachingsecond magnetic head assemblies to the arms of the carriage to which thefirst magnetic head assemblies have been fixed, and

FIG. 10 is a cross-sectional view illustrating a step of fixing thesecond magnetic head assemblies to the arms by calking.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiment of the present invention will now be described with referenceto the accompanying drawings.

A description will first be given of a magnetic disk drive to which theassembly method of the present invention is applied, for example, a harddisk drive (HDD).

As is shown in FIG. 1, the HDD has a rectangular housing 1 with an opentop surface. For example, three magnetic disks 2 are vertically arrangedat predetermined intervals in a right-hand region in the housing 1. Thecentral portions of the magnetic disks 2 are coupled to a hub 3 of aspindle motor (not shown) mounted in the housing 1. The magnetic disks 2are rotated at high speed by the spindle motor.

A carriage 4 rotatable on a support shaft 30 fixed on the housing 1 iscontained in a left-hand region in the housing 1. As is shown in FIGS. 2and 3, four plate-like arms 5 extending in a axis perpendicular to theaxis of the support shaft 30 are provided on the carriage 4. These arms5 are juxtaposed at predetermined intervals. Outer peripheral portionsof the magnetic disks 2 are inserted between adjacent two of the arms 5,respectively. The arms 5 extend along recording surfaces formed on topand bottom surfaces of the disks 2. A through-hole 6 is formed in adistal end portion of each arm 5. The through-holes 6 of the arms 5 arecoaxial with each other, and the center axes of the through-holes 6 areparallel to the support shaft 30.

Three first magnetic head assemblies 7a having magnetic heads 11a facingthe upper recording surfaces of the associated magnetic disks 2 arefixed to the upper three arms 5 of the arms 5. Second magnetic headassemblies 7b having magnetic heads 11b facing the lower recordingsurfaces of the associated magnetic disks 2 are fixed to the lower threearms 5 of the arms 5.

As is shown in FIGS. 2 and 3, each first magnetic head assembly 7aincludes an elongated belt-shaped suspension 8a, an upward mount portion9a provided on a proximal end portion of the suspension 8a, and themagnetic head 11a supported downward on a distal end portion of thesuspension 8a via a gimbal 10a. Reference numeral 12a denotes a leadwire extending along a right-hand edge portion of the suspension 8a fromthe magnetic head 11a.

As is shown in FIGS. 2 and 5, the second magnetic head assembly 7b hassubstantially the same structure as the first magnetic head assembly 7a.A downward mount portion 9b is provided on a proximal end portion of abelt-shaped suspension 8b, and the magnetic head 11b is supported upwardon a distal end portion of the suspension 8b via a gimbal 10b. Referencenumeral 12b denotes a lead wire extending along a right-hand edgeportion of the suspension 8b from the magnetic head 11b.

Each of the mount portions 9a and 9b has a cylindrical shape such thatit can be fitted in the through-hole 6. Each of the first magnetic headassemblies 7a is coupled to the carriage 4 by inserting the mountportion 9a in the through-hole 6 of the associated arm 5 from the bottomand fixing the mount portion 9a by calking. Each of the second magnetichead assemblies 7b is coupled to the carriage 4 by inserting the mountportion 9b in the through-hole 6 of the associated arm 5 from the topand fixing the mount portion 9b by calking.

A carriage assembly 13 is constituted by the carriage 4 and three pairsof first and second magnetic head assemblies 7a and 7b sandwiching themagnetic disks 2.

As is shown in FIG. 1, a control circuit board 14, which is connected tothe lead wires 12a and 12b of the magnetic heads 11a and 11b via a flatcable 15, is disposed in the left-hand region in the housing 1. Inaddition, a voice coil motor 16 for rotating the carriage 4 is containedin the housing 1. Each of the magnetic heads 11a and 11b is movedbetween an innermost peripheral portion and an outermost peripheralportion of the associated magnetic disk 2 by a thrust force generated bythe voice coil motor 16. Thereby, data is recorded on the recordingsurfaces of each magnetic disk, or the recorded data is reproduced.

The method of the present invention is applied to the assembling of thecarriage assembly 13 of the magnetic disk drive having the aboveconstruction. The assembly method according to the embodiment of theinvention will now be described.

Specifically, when the first and second magnetic head assemblies 7a and7b are to be attached to the carriage 4, the carriage 4 is first set onan alignment jig (not shown).

Then, either the first magnetic head assemblies 7a or second magnetichead assemblies 7b, e.g. first magnetic head assemblies 7a, are attachedto the associated arms 5.

In this case, as shown in FIGS. 3 and 4, the magnetic head assemblies 7aare arranged successively on the bottom surface of the uppermost arm 5,the bottom surface of the immediately below (middle upper) arm 5, andthe immediately below (middle lower) arm 5, and the mount portions 9aare fitted in the associated through-holes 6. Thereby, the threemagnetic head assemblies 7a are situated in predetermined positions.

Through the above steps, the three first magnetic head assemblies 7afacing the top surfaces of the magnetic disks 2 are easily attached tothe distal end portions of the arms 5 by making use of relatively widespaces.

After the first magnetic head assemblies 7a have been attached, acalking steel ball 17 is passed under pressure through the inner holesof the mount portions 9a, as shown in FIG. 4. Thus, the slightly movablemount portions 9a are fixed to the arms 5 by calking. Specifically,since the steel ball 17 has a diameter slightly greater than the insidediameter of each mount portion 9a, the mount portion 9a is deformed soas to bite into the inner surface of the through-hole 6 with the passingof the steel ball 17 under pressure and the three magnetic headassemblies 7a are fixed to the arms in the same direction.

After the downwardly directed first head assemblies 7a have been fixedto the bottom surfaces of the upper three arms 5, the upwardly directedsecond head assemblies 7b are attached to the top surfaces of the arms5. Specifically, as shown in FIGS. 5 and 6, the magnetic head assemblies7b are arranged successively on the top surface of the middle upper arm5, the top surface of the middle lower arm 5, and the top surface of thelowermost arm 5, and the mount portions 9b are fitted in the associatedthrough-holes 6. Thereby, the three magnetic head assemblies 7b aresituated in predetermined positions so as to face the already fixedfirst magnetic head assemblies 7a, respectively.

At this time, since the adjacent first magnetic head assemblies 7a havealready fixed in the preceding step and are not dislocated even if anexternal force is applied. Thus, the second magnetic head assemblies 7bare easily attached to the arms 5 by making use of the space between thearms, with no need of careful handling.

After the second magnetic head assemblies 7b have been attached, thecalking steel ball 17 is passed under pressure through the inner holesof the mount portions 9b, as shown in FIG. 6. Thus, the slightly movablemount portions 9b are fixed to the arms 5 by calking. Specifically,since the steel ball 17 has a diameter slightly greater than the insidediameter of each mount portion 9b, the mount portion 9b is deformed soas to bite into the inner surface of the through-hole 6 with the passingof the steel ball 17 under pressure and the three magnetic headassemblies 7b are fixed to the arms in the same direction, as with thecase of the downwardly directed magnetic head assemblies 7a.

Accordingly, the downwardly directly magnetic head assemblies 7a andupwardly directly magnetic head assemblies 7b can be easily fixed to thecarriage 4, unlike the prior art. Therefore, the assembly workefficiency can be enhanced and the work time can be decreased.

In the above embodiment, after the downwardly directly magnetic headassemblies 7a are attached to the carriage 4, the upwardly directly headassemblies 7b are attached to the carriage 4. Inversely, after theupwardly directly magnetic head assemblies 7b are attached to thecarriage 4, the downwardly directly head assemblies 7a may be attachedto the carriage 4, with the same advantage obtained.

The method of the present invention is applicable not only to theassembling with the magnetic head assemblies having the mount portionsof the same diameter, but also to the so-called "interlock-type"assembling with a combination of magnetic head assemblies havinglarge-diameter mount portions and small-diameter mount portions.

A second embodiment of the present invention, which relates to theinterlock-type assembling, will now be described with reference to FIGS.7 to 10.

The second embodiment differs from the above-described first embodimentwith respect to the structure wherein the downwardly directed firstmagnetic head assemblies 7a are provided with cylindrical first mountportions 20a each having an outer diameter substantially equal to thediameter of each through-hole 6 and the upwardly directed secondmagnetic head assemblies 7b are provided with second mount portions 20bto be fitted in the first mount portions 20a within the through-holes 6,i.e. cylindrical second mount portions 20b each having an outer diametersubstantially equal to the inner diameter of each first mount portion20a.

The method of the second embodiment will now be described with referenceto magnetic head assemblies 7a and 7b having the mount portions 20a and20b.

Specifically, when the first and second magnetic head assemblies 7a and7b are to be attached to the carriage 4, the carriage 4 is first set onan alignment jig (not shown).

Then, the first magnetic head assemblies 7a are 10 attached to theassociated arms 5. As is shown in FIGS. 7 and 8, the magnetic headassemblies 7a are arranged successively on the bottom surface of theuppermost arm 5, the bottom surface of the immediately below (middleupper) arm 5, and the immediately below (middle lower) arm 5, and themount portions 20a are fitted in the associated through-holes 6.Thereby, the three magnetic head assemblies 7a are situated inpredetermined positions. A cap 20d having a mount portion 20c, which issubstituted for the first mount portion 20a, is arranged on the bottomsurface of the lowermost arm 5 and fitted in the through-hole.

Thereby, the three first magnetic head assemblies 7a facing the topsurfaces of the magnetic disks 2 are easily attached to the distal endportions of the arms 5 by making use of wide spaces provided byalternate arrangement of the head assemblies.

After the first magnetic head assemblies 7a have been attached, acalking steel ball 21a having a diameter slightly greater than the innerdiameter of each first mount portion 20a and the mount portion 20c ispassed through the inner holes of the mount portions 20a and 20c underpressure. Thus, with the passing of the steel ball 21a under pressure,each mount portion is deformed so as to bite into the inner surface ofthe associated through-hole and fixed by calking. Thereby, the threefirst magnetic head assemblies 7a and the cap 20d are fixed to the armsin the same direction.

After the first magnetic head assemblies 7a have been fixed to thebottom side of the arms 5, the second magnetic head assemblies 7b areattached to the opposite side of the arms 5.

As is shown in FIGS. 9 and 10, a cap 20f having a mount portion 20e,which is substituted for the second mount portion 20b, is engaged in thetop surface of the uppermost arm 5. The second magnetic head assemblies7b are arranged successively on the top surface of the middle upper arm5, the top surface of the middle lower arm 5, and the top surface of thelowermost arm 5, and the second mount portions 20b are fitted in theassociated through-holes 6. The inserted end portions of the secondmount portions 20b and 20e are inserted in the first mount portions 20aand the mount portion 20C of the cap 20f of the already fixed magnetichead assemblies 7a. Thereby, the magnetic head assemblies 7b aresituated in predetermined positions.

In this case, the first mount portions 20a of the first magnetic headassemblies 7a mated with the second mount portions 20b have already beenfixed in the preceding step, and therefore are not dislocated even if anexternal force is applied. Thus, the second magnetic head assemblies 7bare easily attached to the arms 5 by making use of the space between thearms, with no need of careful handling.

After the second magnetic head assemblies 7b have been attached, acalking steel ball 21b having a diameter slightly greater than the innerdiameter of each of the second mount portion 20b and 20e is passedthrough the inner holes of the mount portions 20b and 20e underpressure, as shown in FIG. 10. Thus, with the passing of the steel ballunder pressure, each mount portion 20b, 20e is deformed so as to biteinto the inner surface of the associated mount portion 20a, 20c andfixed to the mount portion 20a, 20c by calking. Thereby, the threemagnetic head assemblies 7b are fixed to the arms in the same direction.

As has been described above, even in the case of the interlock-typeassembly method, the downwardly directed magnetic head assemblies 7a andupwardly directed magnetic head assemblies 7b can be fixed through easysteps.

As with the above-described first embodiment, in the second embodiment,all the magnetic head assemblies 7a and 7b can be fixed to the arms ofthe carriage 4 with a lesser work load. Therefore, the assembly workefficiency can be enhanced and the work time can be decreased.

In the above embodiments, six magnetic head assemblies are attached tothe carriage. However, the number of magnetic head assemblies is notlimited to six. For example, four, eight, or a greater even-number ofmagnetic head assemblies may be fixed to the carriage by the method ofthe present invention.

Additional advantages and modifications will readily occur to thoseskilled in the art. Therefore, the invention in its broader aspects isnot limited to the specific details, and illustrated examples shown anddescribed herein. Accordingly, various modifications may be made withoutdeparting from the spirit or scope of the general inventive concept asdefined by the appended claims and their equivalents.

What is claimed is:
 1. A method of assembling a carriage assembly of amagnetic disk drive, the carriage assembly including a carriage with aplurality of arms arranged in parallel at predetermined intervals andhaving end portions in which through-holes are formed, a plurality offirst magnetic head assemblies with cylindrical first mount portionseach having an outer diameter substantially equal to the diameter ofeach of the through-holes, and a plurality of second magnetic headassemblies with cylindrical second mount portions each having an outerdiameter substantially equal to the inner diameter of each of the firstmount portions, each of the first magnetic head assemblies being fixedto one side surface of an associated one of the arms with the firstmount portion being engaged in the through-hole of the associated arm,each of the first magnetic head assemblies facing one surface of anassociated one of magnetic disks situated between adjacent ones of thearms, each of the second magnetic head assemblies being fixed to theother side surface of an associated one of the arms with the secondmount portion being engaged in the first mount portion engaged in thethrough-hole of the associated arm, each of the second magnetic headassemblies facing the other surface of the associated one of themagnetic disks, each magnetic disk being interposed between a pair ofthe mutually facing first and second magnetic head assemblies,saidmethod comprising the steps of: fixing each of the first magnetic headassemblies to one side surface of an associated one of the arms, byfitting and calking the first mount portion of the first magnetic headassembly in the through-hole of the associated arm; and fixing each ofthe second magnetic head assemblies to the other side surface of theassociated one of the arms, after the first magnetic head assemblies arefixed, by fitting and calking the second mount portion of the secondmagnetic head assembly in an inner hole of the first mount portion fixedin the through-hole of the associated arm.
 2. A method according toclaim 1, wherein said step of calking the first mount portion includespassing a steel ball under pressure through the inner hole of the firstmount portion fitted in the throughhole, the steel ball having adiameter greater than the inner diameter of the inner hole of the firstmount portion.
 3. A method according to claim 1, wherein the step ofcalking the second mount portion includes a step of passing a steel ballunder pressure through an inner hole of the second mount portion engagedin the inner hole of the first mount portion, the steel ball having adiameter greater than the diameter of the inner hole of the second mountportion.